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Definition: Delusions from Black's Medical Dictionary, 43rd Edition

An irrational and usually unshakeable belief held by some individuals. They fail to respond to reasonable argument and the delusion is often paranoid in character with a belief that they are being persecuted. The existence of a delusion of such a nature as to seriously influence conduct is one of the most important signs in reaching a decision to arrange for the compulsory admission of a person to hospital for observation. (See MENTAL ILLNESS.)

Summary Article: Delusions
From The Corsini Encyclopedia of Psychology and Behavioral Science

There is no widely accepted definition of delusion. Delusions are often described in textbooks as being defined since Karl Jaspers as false, subculturally atypical beliefs, strongly maintained in the face of counterargument. Yet such definitions fail to capture either the rich diversity or key features of delusions.

Common delusions include persecution (there is a plot or conspiracy against the subject; these are the most common delusional beliefs); grandiosity (the subject is an important personage); erotomania (people delusionally believe that someone is deeply in love with them); and control (the belief that one’s actions, thoughts, or feelings are being controlled by others). The majority of delusions concern the subjects’ position in the social world, or reflect central existential issues in their lives, and these beliefs are indeed often false, atypical, and strongly maintained.

It is however possible that a delusion (such as that of one’s partner being unfaithful) may accidentally be true. Levels of conviction in delusions may also vary with time. Some delusions may be paradoxically true rather than false (e.g. the delusion that one is mentally ill), and others may be not beliefs but rather delusional value judgments, thoughts, perceptions, memories, inner experiences, and moods (Sims, (2003)). The “delusionality” of delusions of control, for example, arises directly from a disturbed experience of one’s own agency, rather than with beliefs about such experiences.

As Jaspers himself reported, to “say simply that a delusion is a mistaken idea which is firmly held by the patient and which cannot be corrected gives only a superficial and incorrect answer” (Jaspers, 1913/1997, p. 93). Delusions instead reflect a fundamental disturbance in our relation to reality and the integrity of the self, which is hard to pinpoint in a definition. Jaspers distinguished between primary delusions, which arise in an ultimately unintelligible way in our contact with reality itself, and secondary delusions, which are intelligible attempts to understand baffling experiences. Although Jaspers’ doctrine of the “ununderstandability” of primary delusions has often been criticized, it is important to recognize that his point is not to preclude a reflective understanding of what the deluded person says, what psychodynamics underpin it, or what symbolism it expresses. His point is rather that we always fall short of inhabiting such beliefs or experiences from a first-person perspective.

Psychoanalytic Perspectives

Sigmund Freud described delusions as “applied like a patch over the place where originally a rent had appeared in the ego’s relation to the external world” (Freud, 1924/1981, p. 215). He distinguished between neurotic and psychotic conditions as follows. In the neuroses, people attempt to adapt to an incompatible reality by defending against their own feelings. The symptoms that result are the product of the internal conflicts within patients when they try to remodel their desire. In the psychoses, by contrast, people attempt to solve their con-flicts with reality not by altering their feelings, but by withdrawing from or disavowing reality and replacing it instead with fantasies that are treated as realities.

In the 1960s the psychiatrist Thomas Freeman ex-tended the psychoanalytic understanding of delusion (Freeman, Cameron, & McGhie, (1966)). Although some delusions can be understood as fantasized replacements for lost relationships, others consist of misinterpretations of experiences with others from whom the subject has not become completely detached. Accordingly, the delusional subject attempts to bend or exaggerate reality to make it more tolerable and less threatening of the subject’s sense of himself or herself, rather than completely substitute for it, and the delusions are the outcome of such defensive maneuvers.

More recent psychoanalytic thinking on psychosis has been organized not around the concept of delusion, but rather by attempts to understand the nature of omnipotent fantasy, including the mental mechanisms of splitting, projection, projective identification, and symbolic condensation. All of these processes may be implicated in the formation of delusions, but none is specific to it.

Phenomenological Perspectives

Phenomenology aims to elucidate the lived, nonreflec-tive, and immersed experience of being a self in relation to a meaningful environment that includes other selves. Accordingly, the phenomenological understanding of delusions—in particular of schizophrenic delusions—views what is specific to it as already contained in germ in a specific predelusional disturbance of immersed participation. More specifically, most phenomenological psychiatrists track this disturbance back to fragile temporal and corporeal processes that underpin the constitution of the self. Phenomenologists view the delimitation of self from others as arising out of an organism’s nonreflective interactions with its social and physical environment. Disturbances of this process result in disturbances in the boundary between self and world, and delusional beliefs and experiences carry this fundamental disturbance in reality contact inscribed within them.

Most phenomenological accounts take their lead from the first two stages of Klaus Conrad’s ((1958)) developmental account of delusion in paranoid schizophrenia. In the initial predelusional “trema” stage, people start to vaguely feel that all is not well with themselves and/or the world. They may complain of an unspecific groundlessness, confusion about or lack of a sense of their own identity, diminished sense of aliveness, and lost automatic connection with reality. The body may become experienced as an object rather than as a living subject, self and others may start to become confused, the objective character of reality may be lost, and the delusional experience of reference—a sense that everything seen has been constructed for the sake of the subject—may begin (Parnas & Sass, (2001)).

In Conrad’s second stage, “apophany,” delusions proper arrive. Now the trema is intuitively resolved into one particular revelatory meaning, and subjects take themselves to now “understand” what had previously only been confusingly signaled. Relief is experienced from the diffuse tension and terror of the trema, and a monothematic reflective grasp of what is happening (e.g. there is a government plot against me) takes the place of the prereflective but destabilized grasp (“something is up”) that subjects had on their situation.

Cognitive Science Perspectives

Unlike psychoanalytic and phenomenological theories, cognitive psychological theories are driven by a psychological understanding of the human being as constantly and actively attempting to interpret, or make reflective sense of, their personal situation. Thus Brendan Maher ((1974)) suggested that delusional beliefs represent rational attempts to make sense of abnormal experiences (e.g. hallucinations or passivity experiences). Phillipa Garety by contrast has suggested that abnormal processes of reflective sense making may be implicated in delusion formation (Garety & Freeman, (1999)). She found, for example, that patients with delusions tend to jump to conclusions on the basis of surprisingly little evidence.

Several difficulties confront such cognitive psychological accounts. First, delusions—especially primary delusions—do not present themselves as active interpretive products, but rather as spontaneous and passive revelations in thought, feeling, or perception. Even the delusional explanations that patients offer appear to be more post-hoc rationalization than genuine justification. Second, Garety also found that the hasty reasoning style of delusional patients makes them equally likely to quickly give up their beliefs, which makes it hard to understand the typical intransigence of the delusional subject. It is also important to recognize that the explanatory task, in understanding delusional intransigence, is not merely how unshakeable beliefs arise, but how unshakeable beliefs with the face-value implausibility of delusions could arise. Finally, Maher’s theory does not explain why patients fail to accept the obvious explanation that they are hallucinating or experiencing passivity experiences.

Cognitive neuropsychological perspectives, as opposed to cognitive psychological perspectives, are typically not governed by an understanding of the individual as an active reflective sense-maker, and hence they are not restricted to theorizing about delusions in such terms. Hemsley ((2005)) provides a good example with a speculative model of schizophrenia as being due to a deficiency in the influence of background context on current task performance. This model ties together neurological (e.g., frontotemporal functional disconnections), information processing (e.g., sensory and motor program disturbances), and psychological (a range of symptoms including delusional beliefs and experiences) levels of explanation.

Primary delusions are accordingly theorized by Hemsley as resulting from a mismatch between tacit and automatically deployed frames of reference and the sensory inputs to which they are applied. Delusional experience in the trema is also understood as due to a breakdown in gestalt or context perception. Decontextualized stimuli, including those normally screened out as irrelevant, may appear equally salient, and sec-ondary delusional beliefs may reflect a search for the meaning of stimuli that would not normally have come to conscious attention. Hemsley speculates, for example, that delusional thinking about causal relationships may result from a failure of context to constrain judgments about the relevance of the co-occurrence of stimuli.

Future work on delusion will need to weave together the above approaches. From epistemology we require adequate understandings of what it is that grounds our relation to reality (e.g., reflective thought or bodily praxis) and what it is to lose that relation. From psychoanalysis we require an updating of the theory of delusion in the light of post-Kleinian understandings of the nature of unconscious fantasy. From phenomenology we require a precise understanding of how delusional distortions of reality contact manifest in the various (linguistic, corporeal, behavioral, intersubjective, and reflective) dimensions of human existence. And from cognitive neuropsychology we require theories aptly constrained by the above psychological domains, but informed by the latest neuro-imaging research.

See also

Delusional Disorder, Disordered Thinking; Irrational Beliefs.

  • Conrad, K. (1958). Die beginnende Schizophrenie. Versuch einer Gestaltanalyse des Wahns. Stuttgart: Thieme.
  • Freeman, T., Cameron, J. L., & McGhie, A. (1966). Studies on psychosis: Descriptive, psychoanalytic, and psychological aspects. New York: International Universities Press.
  • Freud, S. (1981). On psychopathology. Harmondsworth: Penguin Books.
  • Garety, P., & Freeman, D. (1999). Cognitive approaches to delusions: A critical review of theories and evidence. British Journal of Clinical Psychology, 38, 2, 113-154.
  • Hemsley, D. R. (2005). The development of a cognitive model of schizophrenia: Placing it in context. Neuroscience and Biobehavioral Reviews, 29, 977-988.
  • Jaspers, K. (1913). Allgemeine psychopathologie. Berlin, Springer-Verlag. (Trans. J. Hoenig, & M. W. Hamilton) (1963). General Psychopathology. Chicago: University of Chicago Press. New edition (2 vols., paperback), with a foreword by McHugh, Paul R., (1997). Baltimore: Johns Hopkins University Press.
  • Maher, B. (1974). Delusional thinking and perceptual disorder. Journal of Individual Psychology, 30, 98-113.
  • Parnas, J., & Sass, L. (2001). Self, solipsism, and schizophrenic delusions. Philosophy, Psychiatry, & Psychology, 8, 2/3, 101-120.
  • Sims, A. (2003). Symptoms in the mind (3rd ed.). London: Elsevier.
  • Suggested Readings
  • Berrios, G. (1996). Delusions. In Berrios, G., The history of mental symptoms: Descriptive psychopathology since the 19th century (ch. 6). Cambridge: Cambridge University Press.
  • Freeman, D., Bentall, R., & Garety, P. (2008). Persecutory delusions: Assessment, theory and treatment. Oxford: Oxford University Press.
  • Munro, A. (2008). Delusional disorder: Paranoia and related illnesses. Cambridge: Cambridge University Press.
    K. W. M. FULFORD
    University of Warwick Medical School, United KingdomUniversity of Warwick Medical School and Fellow of St Cross College, Oxford, United Kingdom
    Copyright © 2010 by John Wiley & Sons, Inc. All rights reserved.

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